A number of vehicles, such as forklift trucks, operate on liquid phase LP gas fuel that is typically provided in refillable or replaceable fuel cylinders, which are frequently maintained by third parties.
In order to connect a motor fuel carburetion line with a fuel cylinder, a female connector mounted on the end of the carburetor fuel line engages a male connector on the fuel cylinder. The male connector usually is a threaded acme fitting on an outlet valve that is mounted on the service valve outlet of the fuel cylinder. The fuel line connector mates with the male acme connector of the outlet valve. The fuel line connector can include an outwardly biased, normally closed fuel line connector valve. The fuel cylinder outlet valve and fuel line connector valve mate when the connectors are threaded together. This enables both valves to open, permitting fuel flow from the pressurized fuel cylinder to the motor. The service valve on which the outlet valve is mounted includes a manually operable shutoff valve. A quick fit connector also can be used.
To fill such a fuel cylinder, fuel from a pressurized LP gas storage tank can be transferred by a fuel hose through the same service valve inlet of the fuel cylinder by means of a motor fuel filler valve that is connectable by a threaded connection to the acme fitting on the outlet valve connected to the service valve outlet. A quick fit connector also can be used.
In both cases, two annular seals are usually employed for the connection, an O ring seal and a flat gasket seal incorporated in the outlet valve on the fuel cylinder. These seals are prone to leakage, especially on connecting and disconnecting the connectors, and the seals wear out and break from time to time and require replacement. A problem with replacement is that the seals needing replacement are in the control of the fuel cylinder provider, and the vehicle operator can be provided with a leaky connection over which he has no control. This can result in substantial fuel loss at the vehicle operator's expense.
An object of the present invention is to provide a fuel line connector having an improved, replaceable tip seal that can be mounted on the fuel line in order to provide an additional, effective seal against leakage, and which can be maintained and replaced by the party using the vehicle or filling the fuel cylinder.